[trunker]

strain refers to something or someone that has a force being acted upon them or it. or they are applying the force . so for example :

the table broke under the strain of too much weight. or he went crazy because of the strain of too much work/pressure.

so strain is a resisting action.

tension refers to the force itself.

so you could say: the tension strained the string and it broke.

or

i did some some stretching exercise today, and when i bent down to touch my toes i could feel the tension in my back. i stretched too much and i strained my back ( from the tension).

this is the literal translation of tension.

ok i asked a japanese friend and he said this might help to define tension in a social sense:

kin paku kan or kin cho kan

i hope that helps.